1. Field of the Invention
The present invention relates to glycine derivatives which act as muscarinic receptor antagonists. The present invention also relates to processes for the preparation of such a glycine derivative, compositions which contain such a glycine derivative, and therapeutic uses of such a glycine derivative, as well as devices which contain such a glycine derivative and combinations which contain such a glycine derivative.
2. Discussion of the Background
Quaternary ammonium salts which act as muscarinic (M) receptor antagonist drugs are currently used in therapy to induce bronchodilation for the treatment of respiratory diseases. Examples of well known M receptor antagonists are for instance represented by ipratropium bromide and tiotropium bromide.
Several chemical classes which act as selective M3 receptor antagonist drugs have been developed for the treatment of inflammatory or obstructive airway diseases such as asthma and chronic obstructive pulmonary disease (COPD).
Quinuclidine carbamate derivatives and their use as M3 antagonists are disclosed e.g. in WO 02/051841, WO 03/053966, and WO 2008/012290, which are incorporated herein by reference in their entireties.
Said M and M3 receptor antagonists are currently administered through inhalation route in order to deliver the drug directly at the site of action, thus limiting the systemic exposure and any undesirable side effect due to systemic absorption. However, even though the systemic exposure may be reduced through the inhalatory route, the compounds of the prior art may still, at least potentially, exhibit undesired side effects due to systemic absorption. Therefore, it is highly desirable to provide M3 receptor antagonists which are able to act locally, while having high selectivity and plasmatic instability. Said drugs, once adsorbed, are degraded to inactive compounds which are deprived of any systemic side effects typical of muscarinic antagonists.
WO 2010/072338, which is incorporated herein by reference in its entirety, describes azonia-bicyclo[2.2.2]octane compounds which act as muscarinic receptor antagonists, further possessing the above therapeutically desirable characteristics.